package com.atguigu.zy.interview.javase;

import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;

/**
 * @author Jungle
 * @create 2022-09-14 16:27
 */
public class Test1 {
    public static void main(String[] args) {
       Map<Object, Object> map = new HashMap<>();
        HashSet<Object> objects = new HashSet<>();
        objects.add(null);
        map.put(null, null);

        System.out.println(map+"\t"+objects);

    }
}
